Fire pump



June 19, 1956 D. F. THOMAS ETAL 2,750,893

FIRE PUMP Filed Sept. 19, 1949 3 Sheets-Sheet 1 ZSrmentor .Dam'a' F.Thomas 8;, Georqe A. fiazhbur-n M -aw June 19, 1956 D. F. THOMAS ETAL2,750,393

FIRE PUMP Filed Sept. 19, 1949 a Sheets-Sheet 3 F 6 7 3nventor David EThomas M Gearye A. fimhbw-n M m (Ittorneg United States FIRE PUMPApplication September 19, 1949, Serial No. 116,538

4 Claims. (Cl. 103-166) The present invention relates to an improvementin fire pumps and deals particularly with a multi-stage pump having alast stage which may or may not be employed.

In the production of centrifugal pumps of the type used in fire fightingapparatus and the like, the use of unusually high pressures is sometimesrequired. During the normal operation of the pump sufficient pressuremay often times be built up to serve to best advantage in fighting thefire. However, from time to time increased pressure at the outlet of thepump is desirable, such as would be the case in dealing with a fire onan unusually high structure where the stream of water must be unusuallylong or where a finely divided stream of water, known as mist or fog, isdesired. Under such circumstances, it is often highly desirable to beable to employ an additional stage which will increase the dischargepressure of the pump materially.

An object of the present invention lies in the provision of a pumppreferably having a plurality of impellers and which if desired may beconnected either in series or in parallel. An additional impellerrotates in unison with the plurality of impellers, the additionalimpeller under ordinary circumstances rotating freely within itsempeller chamber. When it becomes necessary to employ an additionalstage on the pump to develop a higher pressure, the normally operableimpellers are connected in series and the last impeller of the series isconnected to the intake of the normally unused impeller. As a resulthigher pressures can be developed almost instantaneously when desiredwithout the necessity of providing costly clutches or similar means.

A feature of the present invention lies in the provision of acentrifugal pump having a pump housing normally enclosing two or moreimpellers and in providing means whereby these impellers may beconnected in series. An auxiliary pump housing is secured to the firstmentioned pump housing in such a manner that the impeller shaft of themain pump extends into the impeller chamber of the auxiliary pumphousing. When the auxiliary pump is not in use the impeller thereofrotates freely in its housing. However, when additional pressure must bedeveloped the outlet of the main pump housing is connected to the intakeof the auxiliary pump housing and the impeller of the auxiliary pumpacts to increase the pressure developed by the pump.

An added feature of the present invention lies in the provision of apump having a main pump housing employing two or more impellersrotatably supported-upon an impeller shaft and in providing a gear caseor transmission for driving this impeller shaft. The gear case ismounted on one side of the main pump housing while an auxiliary pumpcasing is mounted upon the opposite side thereof. With this constructionthe normally unused impeller is mounted in close relation to the mainpump and does not interfere with the normal use, operation, or repair ofthe main pump or the gear box.

The main pump housings are usually formed in at least two parts whichare separable along a horizontal division of the drawings.

ice

line extending through the impeller shaft. As a result if the repair orreplacement of any part of the main pump is required, the top portion ofthe pump may be disengaged from the bottom portion thereof so that theimpeller chambers and the impeller shaft are exposed. The gear box isusually produced with removable sides or removable side plates whichsupport impeller shaft bearings as well as bearings for the other shaftssupporting the gears. If the auxiliary stage of the pump is attached tothe gear box so as to project from the gear box in a direction oppositethe main pump housing, this auxiliary housing must be dismantled orremoved before access to portions of the interior of the gear casing maybe obtained. However, by mounting the auxiliary pump housing on the sideof the pump housing opposite that connected to the gear housing, eitherthe main pump housing, the gear housing, or the auxiliary pump housingmay be dismantled without interference with other portions of thestructure. As a result with this arrangement considerable time andeffort is saved in the repair and maintenance of the pump.

An added feature of the present invention lies in the fact that bymounting the auxiliary pump stage on the opposite side of the main pumpcasing from the gear box, the danger of water leaking into the gear caseis obviated. In order to get proper support the housing of the auxiliarypump must be mounted either to the main pump housing or to the gearcase. Where the auxiliary pump housing is mounted to the gear case,there is danger of water leaking along the shaft from the auxiliary pumpinto the gear case. By locating the added stage on the side of the mainpump housing opposite to the gear case, all such danger is obviated.

An added feature of the present invention lies in the simplicity withwhich attachments such as a priming pump clutch or tachometer drive maybe made. If such an added element is used, it is desirable to securethis added element to the gear case. If the added auxiliary pump housingis connected to the gear case the connection with such attachments ismaterially complicated.

An additional feature of the present invention lies in the fact that bymounting the adding auxiliary pump housing on the side of the main pumphousing opposite to the gear case, a better weight distribution isobtained and the resulting unit is more compact. Pumps of the typedescribed are usually supported on the frame or chassis of the mountingthrough suitable mounting pads integral with the main pump housing. Bylocating the gear case on one side of this main housing and mounting theauxiliary pump stage on the opposite side thereof a better balance ofweight is obtained.

These and other objects and novel features of our invention will be moreclearly and fully set forth in the following specification and claims.

In the drawings forming a part of our specification:

Figure 1 is a top plan view of a tire pump showing the constructionthereof.

Figure 2 is an end elevational view of the pump illustrated in Figure 1.

Figure 3 is a cross sectional view through the pump shown in Figures 1and 2.

Figure 4 is an enlarged sectional detail of the seal between theauxiliary stage and the impeller shaft.

Figure 5 is a diagrammatic view of the pump showing the first two stagesarranged in parallel and with the third stage inoperative.

Figure 6 is a diagrammatic view similar to Figure 5 showing the firsttwo stages in series and connected to the third stage.

The pump A is best seen in its entirety in Figures 1 and 2 The pump Aincludes a main pump housing 10 which is of elongated form and includesan inlet and an outlet at both ends of the housing. The gear case fordriving the pump is indicated in general by the numeral 11 and isconnected to one side of the main pump housing as shown in Figures 1 and2. The auxiliary pump housing or added final stage is indicated ingeneral by the numeral 12 and is located on the side of the main pumphousing opposite the side to which the gear case 11 is secured.

The pump A includes an intake manifold 13 Which extends from end to endof the pump housing 10 and includes opposed inlet passages 14 and 15.These inlet passages 14 and 15 communicate with inlet chambers 16 and 17(see Figures 3 and 5) when the pump impellers are in parallel. The pumpalso includes an outlet manifold 19 which is provided with oppositelydirected outlet ports 20. and 21. These ports 2'8 and 21 are controlledby valves 22 and 23 respectively. The outlet manifold 19 and the inletmanifold 13 are generally parallel in relation.

A by-pass arrangement is provided between the outlet of one impeller andthe inlet of the other impeller, the arrangement being generally similarto that illustrated in Patent No. 2,207,575 issued July 9, 1940, to R.R. Boyles et al. This by-pass is controlled by a valve 24, which tendsto close the passage from one intake chamber 17 to one end of the intakemanifold 13. A check valve 28 closes the other side of the chamber 17 toisolate this chamber from the intake manifold. Thus the pump A includestwo stages which may be arranged in series or in parallel and the detailstructure of the passage arrangement which makes this arrangementpossible is not illustrated in view of the fact that it is generally oldin the art, as indicated in the above mentioned patent.

With reference to Figure 3 of the drawings it will be noted that theimpeller shaft 25 extends horizontally through the main pump housing 10and acts as a support for a pair of impellers 26 and 27. The impellersrotate with the shaft 25 and are keyed or otherwise connected thereto.The impellers 26 and 27 are mounted within impeller chambers 29 and 3%respectively and are shaped to receive liquid from the intake chambers16 and 17 through ring shaped openings 31 and 32 encircling the shaft25. The impellers 26 and 27 direct fluid into volutes 33 and 34encircling the impellers and suitable passage means connect the voluteswith the discharge manifold 19. As has bee-n previously described aby-pass extends from the discharge of volute 33 to the inlet chamber 17of the impeller 27 which is controlled by a suitable valve forconnecting the impellers either in series or in parallel.

Figure 5 diagrammatically illustrates the pump A in position forparallel operation. The liquid may enter either end of the intakemanifold 13 through either the port 14 or the port 15, or both. Thisliquid is drawn into the intake chambers 16 and 17 and into theimpellers 26 and 27. The impeller 26 directs fluid through its volute 33and into a by-pass leading to the transfer valve 24. The valve 24directs fluid through the discharge passage 36 into the dischargemanifold 19;.

The impeller 27 directs fluid through its volute 34 and through thedischarge passage into the discharge manifold 19.

In Figure 6 of the drawings the pump is arranged for series operation.In this arrangement the liquid may enter the inlet manifold 13, througheither inlet port 14 or 15, into the intake chamber 16. This liquid isdrawn into the impeller 26 and forced thereby into the volute 33 whichdirects the fluid from the first stage through the transfer valve 24. Inthis position the transfer valve closes the communication between thesuction chamber 17 and one side of the intake manifold 13 and directsfluid from the volute 33 to the suction chamber 17. This fluid underpressure causes the suction check valve 28 to close so that the suctionchamber is disconnected from the intake manifold 13 at both endsthereof.

The impeller 27 directs fluid through the volute 34 and into thedischarge passage 25 connected to the discharge manifold 19.

A suitable bearing and packing gland 37 extends into one side of themain pump housing 10 and a similar packing gland 39 extends into theopposite side thereof. These packing glands prevent the leakage of fluidfrom the inlet passages in the operation of the pump. An intermediatepartition wall 40 encircles the shaft 25 intermediate the impellers 26and 27 so as to separate the impeller chambers 29 and 39. The gear case11 may be formed as best illustrated in Figure 3 of the drawings. Oneend 41 of the shaft 25 is reduced in diameter and is supported by spacedbearings 42 and 43 within the body of the gear case. A gear 44 ismounted on the shaft end 41 between these bearings. The gear 44 is inmesh with an idler gear 45 supported upon a counter-shaft 46 fixedbetween the side walls 47 and 49 of the gear case. Bearings 50 aresupported by the counter-shaft 46 and rotatably sup port the gear 45.

A drive shaft 51 extends into the lower end of the gear case 11 and isarranged in axially aligned relation to a driven shaft 52. The driveshaft 51 is provided with a reducer diameter end 53 which is supportedby a bearing 54 mounted in the driven shaft 52. In this way the shafts51 and 52 are held in proper alignment and may rotate in unison or thedrive shaft 51 may rotate freely relative to the driven shaft 52. Thecombined shafts 51 and 52 extend through opposed closure plates 55 and56. A bearing 57 supported by the closure plate 55 and a pair ofbearings 59 mounted within the closure plate 56 act to support thecombined shafts.

A gear 60 is spline connected to the drive shaft 51 and is slidablelongitudinally thereon, being moved by means of a suitable shifting forkacting in groove 61 integral with the. gear 60. When the gear 61) is inthe position illustrated in Figure 3 of the drawings, the drive shaft 51is connected to the impeller shaft 25 through the gears 60, 45,, and 44.However, when the gear 60 is moved longitudinally on the shaft 51,internal gear teeth 62 engage external gear teeth 63 on the driven shaft52 so as to drive the shafts 51 and 52 in unison. It will be noted thatthe gear 60 may be moved to intermediate position in which it isdisengaged both from the gear 45 and from the gear. teeth 63.

The construction described is all generally old in the art and issimilar to constructions covered by previous patents. The importantfeature of the present invention lies in an addition to the constructionjust described.

It will be noted that the, gear 44 is held in place on the end 41 of heimpeller shaf 25 by means of. a lock nut 64 or other such device. Thegear casing 11 is usually provided with an end closure plate 65 whichencloses the end of the shaft 25 and seals th ear case against the en ryQ i or us In h pa this end pl t 65 has been removed an a xi iary pump sg connected at this point. Such a construction has certain advantages,but also has serious disadvantages. One such disadvantage lies in thefact that leakage along the. shaft 25 from the third stage would cause aleakage of water into the gear casing. Serious damage to the gears andbearings may then readily result. It will be noted that the gear caseand main pump housing are spaced so that leakage of water through thepacking 39 will not enter the gear case. Such a construction could beused in attaching the third stage, but the resulting construction wouldbe somewhat more complicated and somewhat more costly to produce thanthe construction de= scribed herein, and it would require more space.

The pump housing 10 is provided with an integral flange 66 t hi h he auli ry pump housing 12 i attached. T e hous n 12 n ludes a flange 67 degn to exten along. he ange 66 and to be' c ed th re o by ny u tablemeans such as bolts, cap screws or the like. The uxi ary pump housi g 1in lu e a hub porti n 69 h ing a rela ively large diame er Op ing 70 inone en thereof for accommodation of a bearing 71 held in place by ashoulder 68. The opening 70 also accommodates oil for lubricating theshaft. The bearing 71 encircles a portion of the shaft and assists insupporting this shaft.

A reduced diameter portion 72 of the shaft 25 extends through a pair ofseals 73 which tend to prevent the leakage of moisture along the shaft.A sealing unit 74 also encircles the shaft 25 and will later bedescribed in detail. The housing 12 includes an outwardly directedflange 75 which extends outwardly alongside of the impeller 76. Aclosing plate 77 is bolted or otherwise adored by cap screws 79 to themain portion of the pump casing 12. An impeller chamber 80 is providedbetween the closure plate 77 and the main body of the housing 12, toaccommodate the impeller 76. A volute 81 encircles the impeller 76 andcommunicates with a discharge pipe 82 best illustrated in Figure l ofthe drawings.

A pipe 83 communicates with the discharge manifold 19 and is providedwith a shut-off cock 84. The pipe 83 extends angularly to a pointadjacent to the axis of the auxiliary pump 12 and is provided with anattaching flange 85 by means of which it is connected to the hub 86 ofthe closure plate 77.

The seal used in conjunction with the auxiliary pump unit 12 is bestshown in Figure 4 of the drawings and forms an important feature of thepresent invention. The hub portion 69 is provided with an internalshoulder 87 intermediate its ends. The shaft 25 is provided with areduced diameter portion 89 outwardly of the reduced diameter portion 72forming a shoulder 90 between the two parts of different diameter. Aring 91 is provided with an internal aperture of two diameters to snuglyfit the shaft portions 72 and 89 and to engage against the shoulder 90.The ring 91 thus forms a seal with respect to the shaft 25 and is heldfrom axial movement in one direction.

Obviously the ring 91 is sealed to and rotates with the shaft 25. Aretaining ring 92 is provided with a peripheral flange 93 connected tothe auxiliary pump housing 12 by flat head screws 94 or other suitablemeans. The retaining flange 92 is thus sealed to the body of theauxiliary pump housing and fits snugly within the bore of the housinghub 69. A sleeve 95 is slidably supported inwardly of the ring 92 and issealed with respect thereto by an O-ring 96 or by other suitable sealingmeans. A peripheral flange 97 is provided on the sleeve 95 which extendsoutwardly into sliding fit relation with the internal bore of the hub69. Pins 99 or other suitable means are provided for preventing relativerotation between the ring 92 and the sleeve 95. Accordingly the sleeve95 is held from rotative movement, but is free to slide axially withrespect to the shaft 25.

A spring 100 is interposed between the flange 97 of the sleeve 95 andthe fixed shoulder 87 in the housing hub. The spring 100 tends to urgethe sleeve 95to the left as viewed in Figure 4 of the drawings. A shortsleeve like projection 101 on the flange 97 slidably engages the ring 91in one extreme position of the sleeve 95. In the other extreme positionthe projection 101 is spaced from the ring 91 so as not to contact thesame. A spacing ring 102 extends between the impeller 76 and the ring 91so as to space these elements and to hold them in proper relationship.The spacing ring 102 fits within the sleeve 95 freely enough so that thesleeve 95 may move longitudinally of the shaft 25. It will be noted thata space 103 is provided between the impeller 76 and the flange 75 of thehousing 12. As a result when the impeller 76 is in operation pumpingliquid from its intake pipe 83 to the outlet connection 82, water underpressure will extend through this space 103 and urge the sleeve 95 tothe right as viewed in Figure 4. As a result the sleeve projection 101will seal against the ring 91 and a running seal will be provided pastwhich liquid will not leak to any material extent. On the other handwhen the supply of water is cut off from the intake pipe 83 the impeller76 will merely rotate within its chamber without producing any liquidpumping operation and the pressure will be relieved in the space 103. Asa result the spring will force the sleeve 95 out of sealing relationwith the ring 91 and the ring may revolve freely without contacting therunning seal. Thus the seal will not become over-heated through slidingcontact when the impeller 76 is not in the operation of pumping liquidand at the same time the seal will be automatically protected as soon asliquid enters the impeller chamber.

It will be noted that our construction accomplishes certain definitepurposes and has advantages over other more complicated structures. Inthe past the third stage has been mounted upon the gear case where thereis likelihood of water leakage into the gear case and where more of thestructure must be dismantled for inspection or repair. The presentconstruction is economical to produce as no clutch structure is requiredbetween the impeller shaft and the auxiliary stage. The impeller of theadded stage operates continuously with the impeller shaft, but therunning seal which prevents the leakage of liquid from the added stagebecomes automatically disengaged as soon as the impeller of the addedstage ceases to pump liquid. A drain 105 is provided in the casing 12,controlled by a suitable plug 106 or drain cock, so that the impeller 76may rotate freely when the third stage is not in use.

The manner in which the pump A may be transformedfrom parallel operationto series operation through the use of the valve 24 has been describedand is believed obvious from an examination of Figures 5 and 6 of thedrawings. When it is desired to employ the third stage, the hose orother discharge pipe is connected to the discharge 82 of the auxiliarypump unit 12. The valve 84 is operated to open communication betweenthedischarge manifold 19 and the third stage impeller housing. Thevalves 22 and 23 are shut off to close the ends of the dischargemanifold. The water will then flow from the discharge manifold 19through the connecting pipe 83 to the intake of the third stage impeller76 which acts to force the fluid into the third stage discharge at anincreased pressure.

In accordance with the patent statutes, we have described the principlesof construction and operation of our fire pump, and while we haveendeavored to set forth the best embodiment thereof, we desire to haveit understood that obvious changes may be made within the scope of thefollowing claims without departing from the spirit of our invention.

We claim:

1. A centrifugal pump assembly including a main pump housing having amain pump discharge, a shaft extending transversely thereof, a pair ofimpellers on said shaft within said housing, said impellers each havingan inlet and an outlet, means in said housing between the outlet of oneimpeller and the inlet of the other for connecting said impellersselectively in parallel or in series, an auxiliary housing connected tosaid main pump housing, a third stage impeller mounted upon said shaftwithin said auxiliary housing, an impeller chamber within said auxiliaryhousing having an inlet and an outlet, a passage connecting thedischarge of the main pump housing with the intake of the auxiliaryhousing, means for selectively directing fluid through said last namedpassage, and a seal between said shaft and said auxiliary housing, saidseal including a pair of normally spaced elements, means on saidauxiliary housing holding one of said elements fixed from rotationrelative thereto and means supporting the other element rotatable withsaid shaft, means normally urging said elements apart, one of saidelements being axially movable when subjected to pressure within saidauxiliary housing, said one element extending into direct communicationwith said auxiliary housareosos 1 ing pressure, said elements beingengageable to form a running seal when said impeller in said auxiliaryhousing is in liquid pumping operation.

2. A centrifugal pump and auxiliary pump assembly comprising anelongated main pump housing, an impeller shaft journalled in saidhousing and extending transversely thereof, first impellers thereon, agear ease secured to said housing, said gear case including drive gearmeans connected to said impeller shaft for driving the same, anauxiliary housing detachably secured to said main pump housing andhaving an inlet and an outlet, said impeller shaft extending into saidauxiliary housing, intake and discharge passages for said first namedimpellers extending longitudinally of said main p ump housing, anauxiliary impeller within said auxiliary housing and mounted on saidshaft to rotate in unison therewith, a fluid connection from one of saiddischarge passages to the inlet of said auxiliary housing, valve meansfor selectively opening and closing said fluid connection, valve meansfor selectively opening and closing said discharge passages for saidfirst named impellers, whereby said auxiliary impeller may run dry whensaid valve means in said fluid connection is closed, sealing means insaid auxiliary housing encircling said impeller shaft, means operable inthe absence of fluid pressure in said auxiliary housing for reducingfriction between said shaft and said seal when said pump is running dry,and means operable by the presence of fluid pressure in said auxiliaryhousing rendering said last named means inoperable.

3. A centrifugal pump and auxiliary pump assembly comprising a main pumphousing, an impeller shaft extending through said housing, impellers onsaid shaft within said housing intake and discharge passages for saidimpellers in said housing, means connected to said shaft to drive thesame, an auxiliary housing detachably connected to said main pumphousing, an auxiliary impeller in said auxiliary housing, inlet andoutlet passages for said auxiliary impeller in said auxiliary housing, afluid connection extending from one of said discharge passages in saidmain pump housing to said inlet passage in said auxiliary housing, saidimpeller shaft extending into said auxiliary housing and supporting saidauxiliary impeller for rotation with said shaft, means selectivelyopening and closing said fluid connection whereby said auxiliaryimpellerwill run dry when said fluid connection is closed, sealing meansencircling said impeller shaft within said auxiliary housing, meansoperable in the absence of fluid pressure in said auxiliary housing forreducing friction between said seal and said shaft when sai auxiliaryimpeller runs dry, and means operable by fluid pressure in saidauxiliary housing to render said last named means ineffective.

4. The structure described in claim 3 and in which the seal includes apair of normally spaced elements, means on said auxiliary housingholding one of said elements from rotation relative thereto and meanssupporting the other element rotatable with said shaft, means normallyurging said elements apart whereupon said other element may rotatefreely, one of said elements being axially movable when subjected topressure within said auxi ary hous g, said l s named e e ent xt di intodirect communication with the pressure Within said aux li ry housi g,said elem nt i g ngagea e o form a running seal when said impeller insaid auxiliary housing is, in liquid pumping operation.

References Cited in the file of this patent UNITED STATES PATENTS

